(1) Field of the Invention
The present invention relates to pneumatic tires which can remarkably decrease the air-leaking speed at which air leaks when the tire treads on a nail or the like.
(2) Related Art Statement
Heretofore, techniques have been known, in which air leakage is prevented by providing an adhesive rubber layer on an inner surface of a tire and adhering the rubber to a nail or the like entering the tire (Japanese Pat. Application Laid-open Nos. 55-11,998, 55-15,397, 0-64,834, etc.).
However, in such a conventional tire having the adhesive rubber layer provided on the tire inner surface, since the inner surface of the adhesive layer is exposed to air, the layer is deteriorated during use to hinder attainment of the intended object.
In order that the adhesive layer may attain the object of sealing a puncture at a place where the nail enters the tire, the thickness of the adhesive layer there needs to be 3 to 5 mm. Consequently, the tire becomes heavy, so that fuel consumption rate and heat generation resistance are deteriorated. Furthermore, since the adhesive layer gathers near the equatorial plane of the tire due to centrifugal forces during rotation of the tire or since the adhesive layer gathers at one location during long parking, it is difficult to maintain the adhesive layer in a state that the adhesive layer can exhibit its effect wherever a nail enters the tire. In addition, a kneader and a coating system which have not been required in the conventional tire production lines are necessary for the production of such adhesive layers.
Under the circumstances, although conventional tires which are each provided with an adhesive layer at the tire inner surface have certain air leakage-preventing effects, it is an actual situation that such tires have hardly been put into the market as products.